An internal combustion engine includes an engine block defining at least one cylinder having a piston coupled to rotate a crankshaft. A cylinder head cooperates with the piston to define a combustion chamber. A fuel and air mixture is disposed in the combustion chamber and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston. The fuel is provided by at least one fuel injector and the air through at least one intake port, located on an intake side of the cylinder head. The exhaust gasses, on the contrary, are expelled, through at least an exhaust port, located on an exhaust side of the cylinder head opposite to the intake side.
The heat generated by the fuel combustion is partly dissipated by a cooling system, which includes a coolant pump that circulates a coolant, typically a mixture of water and antifreeze, through a cylinder cooling channel, realized in the engine block. The cylinder cooling channel surrounds the engine cylinder and it is in fluid communication with a corresponding cylinder head coolant channel realized in the cylinder head. The coolant exiting from these coolant channels is directed towards a radiator, where the coolant exchanges the heat, received from the engine, with the air of the ambient environment, before returning in the coolant pump.
The cylinder coolant channel includes a single inlet so that the coolant, which flows through the inlet, freely splits in a first part which flows through a first tract of the coolant channel, located on an intake side of the cylinder head, and in a second tract which flows through a second portion of the coolant channel, located on an exhaust side of the cylinder head. The fact that the coolant freely splits in two parts is a drawback of this configuration because it determines a not balanced coolant circulation in the cylinder coolant channel.
Indeed, it has been observed that most of the coolant circulates near the bottom of the cylinder coolant channel and that the speed of the coolant is not uniform in the channel being very high in proximity of the bottom of the channel. The high speed of the coolant causes a cavitation phenomenon at the coolant inlet, while a non-uniform speed of the coolant determines a different coolant effect on the cylinder, which can lead to damage of the engine due to the distortion of a cylinder wall and consequent seizing of the associated piston.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.